A problem with such fuels when used in a liquid state is that because of their very low boiling point they will tend to vaporise in fuel lines unless a sufficient pressure over the vapour pressure at any expected temperature is provided.
In Australian Patent No. 647561 a fuel injection system is disclosed in which liquid LPG is injected into an inlet manifold adjacent to the engine. This region of the engine can get very hot and as such even with excess flow of fuel there can be a problem with vaporisation of fuel. It is desirable therefore that easily vaporisable fuels are injected some distance away from the engine.
It is an object of this invention to provide a fuel injection system for such fuels and in one particular embodiment to modify an internal combustion engine fuelling system adapted to operate on injected petrol so that it can also operate on LPG or CNG liquid injection.
The invention, however, is not particularly directed to this adaptation but is generally directed to a modified fuel injection system.